Dr. Jones was interested in the relationship between sleep and happiness. They gathered 50 participants and assigned them all to sleep for 4 hours per night for 5 days. After 5 days all participants...

Extracted text: Dr. Jones was interested in the relationship between sleep and happiness. They gathered 50 participants and assigned them all to sleep for 4 hours per night for 5 days. After 5 days all participants completed a Happiness Survey. For the next 5 days, all participants were assigned to sleep for 8 hours per night. After 5 days had passed, participants completed the Happiness Survey again. Results showed that when participants slept 8 hours per night, they were happier than when they slept 4 hours per night. What is the participant assignment in this research study? Between groups Matched groups Latin square Within groups